KWAJEX Operations Director Report Number 2

U.S Army Kwajalein Missile Range, Kwajalein Atoll, Marshall Islands

Period: 7 August - 21 August, 1999

Operations Director: T. T. Wilheit

This is the second report to be issued during Kwajex by the Operations Director. This report will not repeat the background information describing the operation as given in the first Operations Director Report. Rather it will concentrate on what we have accomplished and what is left. It will also discuss the difficulties and solutions in the operation.

My term as Operations director covered the period listed above; Eric Smith will serve as Operations Director until his departure on Septmber 3; after that Sandra Yuter will serve as both Operations Director and Science Coordinator until the end of the project.

We have managed to get several data sets that will prove useful. Our premier case occurred on August 11. We had deep convection in the beginning and widespread stratiform rain. We had all three aircraft in the storm for a period and at least two flying well coordinated patterns for hours. The bulk of the data were taken along with good dual doppler coverage. The major disappointment was that there was no satellite overpass on this day. We have worked small to moderate convection with two aircraft and had cases that allowed us to approach intense convection as closely as safety would allow. We have gotten one case of convection, just inside the PR swath, and a good variety of cases within the TMI swath. We have gotten several long (>50km) DC8 runs over rainfall that will be useful for beam filling corrections. Sandra Yuter has put together graphics that allow us to examine the distribution of minutes within cloud as a function of temperature.

Having some experience in hand and a good collection of intelligent experimenters we have been able to refine our tactics to improve some of the sampling. The long lines at a given altitude give a lot of samples at a given temperature. Clearly, this is useful but we also need continuous distributions of samples as a function of temperature. We have introduced spiral maneuvers to provide vertical profiles to complement the discrete legs. We are still working on optimizing the execution of these spirals.

Our mode of operation has strongly favored the sampling of mature and dissipating systems. We need to guess in order to get at growing systems. We have developed a strategy and identified aircraft hours that would otherwise be inefficiently used in order to get some sampling of the growing cells as well as those that do not grow.

We have not sampled intense convection. Safety limits our sampling in this way and WILL NOT BE COMPROMISED.

We also lack, at this point, radiosonde observations at Meck to complement the Tethersonde observations. A very large spare parts shipment should arrive on or about August 22 and we should be able to get these radiosondes working for the last few weeks of the project.

In general, the slow delivery of expendables has been only a token problem to the sounding effort. We had concerns about the relations with the Marshallese on the outer island sites, but relations seem to be going well and we are avoiding any "Ugly American" incidents. The data from the three types of radiosondes have presented challenges which have been handled using the computing power of the Operations Center.

Early in the project, the Tethersonde was damaged by high winds. We implemented a system of warnings from the Aeromet personnel. There were early complaints of over-warning. This is the correct way to err, but even these complaints have died down.

Thus far, the major disappointment of the project have been the extensive grounding of aircraft for mechanical problems. The Convair has been down for about 10 days now. It will be critical to get these assets into the air. The lack of night flying has also limited us to fewer than half of the satellite overpass opportunities.

In the beginning of my tenure, tensions were high within the experiment. Housing difficulties stemming from poor communication and the perception of inequities were a major source of these tensions. It also took time for the personnel from different institutions to learn to work together, and to trust one another. Things have smoothed out a great deal. The flight of the Citation on August 19 is a microcosm of this improved cooperation and trust. Their co-pilot was sick so they were flying with the co-pilot from the Convair. Their radar failed in flight and they allowed the Operations Center to vector them into safe areas of the storm and continued to take data.

In this project, as in any other comparable effort, there have been many problems, malfunctioning equipment, sick pilots, forecast difficulties, complicated operational constraints. However, the personnel have been dedicated to working around these problems to milk the maximum possible scientific results from the experiment. The energy, commitment, and intelligence of these people has been quite impressive.